Tweet
I was at the thrift store, a couple of days ago and came upon one of those deals too good to pass up.
A Brown and Sharpe micrometer (#13 - 1 in.) for only $6.00!
Mic1.png
I figured, even if it's a bit banged up, six bucks is worth it for anything I'd need to measure, just around the house. Right?
Now I need to get it cleaned up and zeroed out. As you can see from the pic, it's off by a little over a thou.
I can take it apart and clean the threads and stuff with something like Zippo fluid (naptha) or mineral spirits then give it a drop of sewing machine oil. I want to make sure that I know how to zero the scale before I go taking things apart but I haven't been able to find a manual for this specific one, on-line... probably because it's a vintage piece of equipment, made before manuals were distributed in PDF format.
I've reset other kinds of mics before. You just loosen the nut, tap the spindle loose with the handle of a screwdriver, etc., then turn the thimble to zero and retighten. Is that the way to do this one, too?
Here's a shot of the end where the nut is:
Mic2.png
I assume that the castle nut is removed with the correct sized spanner (which I don't have) but, looking down the bore of that hole, it's hex shaped. Does that mean you have to use an Allen wrench to adjust something or is that just a way to hold the shaft while you turn the nut?
It doesn't LOOK like it's been bent or banged up.
If you close it all the way to zero, you can't see any light coming through the gap between the anvil and the spindle so the shaft, bore and measuring surfaces are likely to be pretty true. When you close it to zero, it's off by a hair over 0.001", repeatably, so I'm assuming that means the threads aren't messed up and the bow isn't bent.
It'd be nice to get it calibrated to spec if I can but, even if I can only get it close, I think it's still well worth the $6.00.
A Brown and Sharpe micrometer (#13 - 1 in.) for only $6.00!
Mic1.png
I figured, even if it's a bit banged up, six bucks is worth it for anything I'd need to measure, just around the house. Right?
Now I need to get it cleaned up and zeroed out. As you can see from the pic, it's off by a little over a thou.
I can take it apart and clean the threads and stuff with something like Zippo fluid (naptha) or mineral spirits then give it a drop of sewing machine oil. I want to make sure that I know how to zero the scale before I go taking things apart but I haven't been able to find a manual for this specific one, on-line... probably because it's a vintage piece of equipment, made before manuals were distributed in PDF format.
I've reset other kinds of mics before. You just loosen the nut, tap the spindle loose with the handle of a screwdriver, etc., then turn the thimble to zero and retighten. Is that the way to do this one, too?
Here's a shot of the end where the nut is:
Mic2.png
I assume that the castle nut is removed with the correct sized spanner (which I don't have) but, looking down the bore of that hole, it's hex shaped. Does that mean you have to use an Allen wrench to adjust something or is that just a way to hold the shaft while you turn the nut?
It doesn't LOOK like it's been bent or banged up.
If you close it all the way to zero, you can't see any light coming through the gap between the anvil and the spindle so the shaft, bore and measuring surfaces are likely to be pretty true. When you close it to zero, it's off by a hair over 0.001", repeatably, so I'm assuming that means the threads aren't messed up and the bow isn't bent.
It'd be nice to get it calibrated to spec if I can but, even if I can only get it close, I think it's still well worth the $6.00.